nbc news has confirmed senator matt baucus has decided not to run for reelection. this is significant. he voted against background checks but he has an a plus rating. there are adds run against him in advance of 2014. and so we are also looking at the gun control issue in the context of what is going on in boston. so let's start there with the latest. today members of congress are going to learn more about what the fbi knew about the tsarnaev brothers. tamerlan is dead now. dzhokhar tsarnaev accused of using weapons of mass destruction. today the senate intelligence committee. >> there is no way we are going to rest until we see the information at our disposal. >> congressman william ketoing says he is traveling to moscow to get answers. congressman king and mike mccaul waiting. senator lindsey graham blamed a misspelling for the disconnect on dzhokhar tsarnaev's trip to russia. >> i think they did a good job of looking at him. the reason we didn't know he went to russia is because the name was misspelled. >> we are learning about a motive. officials say dzhokhar t